As the field of image processing continues to advance, there is an increasing demand for spatial light modulators (SLMS) that can impress a two-dimensional pattern on a beam of light at high speed and high resolution. Although liquid crystal SLMs have been known for many years, these devices are too slow for some modern applications. A faster alternative to the liquid crystal SLM is a solid state SLM in which a multiple quantum well (MQW) is included in the intrinsic region of a p-i-n diode structure. The use of structures of this kind for light modulation is described, for example, in U.S. Pat. No. 4,525,687, issued to D. S. Chemla et al. on Jun. 25, 1985, and in U.S. Pat. No. Re. No. 32,893, reissued to D. A. B. Miller on Mar. 21, 1989.
In order to achieve high resolution without incurring prohibitive manufacturing costs, it is desirable to fabricate these SLMs as monolithic devices. Because the p-i-n structure is semiconductive, it is necessary to include in the manufacturing process lithographic patterning and etching steps that isolate each picture element in a discrete mesa. Elimination of these steps would result in reduced manufacturing costs.